[lltx] Kerning OTF fonts: 2 other problems

[Khaled Hosny]

On Mon, Feb 28, 2011 at 11:59:27AM +0100, Heilmann, Till A. wrote:
> Am Sun, 27 Feb 2011 18:50:04 +0100 schrieb Ulrike Fischer:
> 
> >> Thanks to your help, I am making progress adjusting the kerning of  
> >> OpenType fonts. There are still some problems, though ...
> >> 1. Curiously, adjusting the kerning does not work for some letter  
> >> pairs and I cannot see a pattern here. Adjusting "ei", for example,  
> >> works just fine but "ev" does not. I got the same results with two  
> >> different fonts (TeX Gyre Bonum and Linux Libertine), so I think it  
> >> is not a font issue but a Lua(La)TeX one.
> >> 
> > 
> > I think it is the font. I don't know much about open type fonts and
> > features etc, but a look at the kerning information of "e" in
> > fontforge seems to indicate that a kern for "ev" and "ew" already
> > exists, and I think this kern "wins". 
> 
> Okay, I see what you mean (I just checked in FontForge too).
> 
> I cannot comment on the technical aspect of this issue but from a
> "philosophical" standpoint it is somewhat bizarre: What good is a
> local or user specific feature file that cannot override the standard
> settings of a font? Is this how OTF features are supposed to (not)
> work? (I know this is probably not the right place to ask this kind of
> question.)

It can be a bug or expected behaviour, I can tell offhand, but you can
try by compiling the .fea file into the font using FontForge (there is a
merge feature file option in file menu) then generating a new font and
testing it in other applications, if it works as you expect then it is a
bug in our side.

Regards,
 Khaled

-- 
 Khaled Hosny
 Egyptian
 Arab